1Being useless or pointless; a waste of time, money, or effort that yields no result. Commonly used as 無駄な〜 (pointless ...), 〜の無駄 (a waste of ...), 無駄に (pointlessly), and 無駄にする (to waste).
今さら言い訳しても時間の無駄だよ。
Making excuses now is just a waste of time.
高い機械を買ったのに使わないなんて、お金の無駄だ。
Buying an expensive machine and then not using it is a waste of money.
彼の助言のおかげで、無駄な作業をせずに済んだ。
Thanks to his advice, I was spared a lot of pointless work.
せっかくの努力を無駄にしたくない。
I don't want all that hard-won effort to go to waste.
電気をつけっぱなしにするのは無駄だから、こまめに消そう。
Leaving the lights on is wasteful, so let's turn them off when we can.